Keeping Up With Technology

Coinjection-Blow System For Barrier PC Bottles

From: Plastics Technology
Issue: March 2007

Multilayer injection-blow molding technology has taken a leap forward with the commercialization of a barrier polycarbonate bottle for medical use.

Multilayer injection-blow molding technology has taken a leap forward with the commercialization of a barrier polycarbonate bottle for medical use. A new coinjection system from Kortec Inc., Ipswich, Mass., produces a three-layer diagnostic bottle with nylon as the barrier core material. Kortec, a specialist in PET preform coinjection systems for stretchblown containers, worked on this project with Uniloy Milacron Inc., Tecumseh, Mich., and GE Plastics, Pittsfi eld, Mass. While PC alone lacks the gas-barrier properties for medical containers, multilayer medical and pharmaceutical bottles of PC, PP, or HDPE with barrier materials are now viewed as a growth area and viable replacements for glass. The clear PC barrier bottle withstands autoclaving and steam sterilization at up to 122 C (252 F). Wall thickness of the 80-cc and 100-cc diagnostic containers is 1.8 mm. A 0.6-mm barrier layer of modifi ed MXD6 nylon from Ems-Grivory America, Sumter, S.C., is surrounded by 0.6-mm inner and outer layers of GE's Lexan 144R PC. John Kermet, Kortec's v.p. of sales and marketing, says his fi rm found that Grivory G21 was the only nylon that maintained its clarity in this application. The fi rst Kortec coinjection system was sold to GE's Polymer Processing Development Center in Pittsfi eld. It utilizes a special 85-ton Uniloy IBS85 injection-blow unit outfi tted with a second injection unit. The four-cavity machine has a 12-sec cycle and produces 1200 bottles/hr. The system can be scaled up to 12 cavities to produce 20 to 25 million bottles/yr. Kortec also sold a coinjection system in Europe for cosmetic containers. The three-layer structure has outer layers of modifi ed Grivory MXD6 nylon and PET in the center. It reportedly provides chemical barrier at lower cost than monolayer nylon or glass. Kortec is also working on three-layer containers of clarifi ed PP and EVOH for pharmaceutical and cosmetics containers up to 50 cc. Meanwhile, Kortec is investigating three-layer cosmetics bottles of PET and Topas cyclic olefi n copolymer (COC) from Topas Advanced Polymers, Inc., Florence, Ky. Kortec: (978) 238-7167/www.kortec. com . Uniloy: (517) 424-8756/www.uniloy. com . GE: (800) 845-0600/www.geplastics. com . Topas: (859) 746-6447/www.topas.com